I believe the answer is as you said; future proofing. 11 looked great when it came out. Look at it now, compared to 14. The real question is whether or not they will keep 14 stuck in DirectX 9, or upgrade to DX11. Currently, they have no plans to upgrade because they feel not enough people support DX11 (which is silly considering most of the graphics cards that actually run this game support DX 11)